The invention is directed to a CD-ROM drive.
A prior art CD-ROM drive is disclosed in the publication, Pioneer Electronic Corporation XP0020066715, Sep. 17, 1996.
In conformity with the demands made of higher read performances, CD-ROM drives work with higher and higher speeds. Proceeding from single, double, through currently 8-fold speed, corresponding drives with speeds in the range from 500 through 6,500 rpm are offered, so that the drives can be set to different speed ranges as needed. By contrast to hard disk drives wherein an extremely precise adjustment and centering is possible due to the permanently installed hard disks, there is the problem given CD-ROM drives that an adequately exact centering can be achieved here for only a relatively small part of the data disks that can be inserted into the drive. Particularly given increasing speeds, this results therein that vibrations and/or running noises that considerably complicate and impede the work execution at a correspondingly equipped personal computer occur due to the non-optimum position given a majority of the data disks that are inserted. In addition to a high noise emission due to the drive, which can also extend onto the entire housing, this leads to unnecessarily high mechanical stresses of the drives, which in turn results in maintenance, repair and other consequential costs. Vibrations that occur at the CD-ROM drive can usually also be transmitted onto neighboring hard disk or floppy disk drives, so that their operation can be sensitively disturbed. Ultimately, this leads to dissatisfaction on the part of the customer, who no longer accepts CD-ROM drives overall.
As known, the tracks in a compact disk are applied in the form of a helix proceeding from inside to outside, whereby all sectors are of equal length, differing from a hard disk. Dependent on the operating mode of the CD-ROM drive, this means either that the speed of the compact disk is linearly reduced from, for example, 6,500 rpm to 3,000 rpm from the first sector arranged at the inside to the last sector arranged at the outside within a predetermined speed range (what is referred to as CLV mode) of that the speed remains constant, with the result that the read speed steadily increases toward the outside (what is referred to as CAV mode). When it then occurs that a sector cannot be faultlessly read, then the drive automatically switches into the next-lower speed range.
An analogous operation is not provided per se when vibrations and/or noise emissions occur. However, it has been disclosed for what are referred to as dual mode CAVICLV drives (see the above-identified product specification of the Pioneer company, September 1996) that an automatic switch from CLV mode into the CAV modes ensues when vibrations occur, i.e. a switch to a speed that is constant within the selected speed range but that is somewhat lower overall, with the advantage that the risk of occurring resonances within the selected speed range is significantly lower given a fixed speed.
The present invention is based on the object of improving a CD-ROM drive in such a way that an operating sequence deteriorated due to vibrations and/or noise emissions can be avoided with simple means and the CD-ROM drive in turn returns into a malfunction-free operation.
In general the present invention is a CD-ROM drive having a plurality of speed ranges selectable in n-fold graduation and, optionally, having constant or linearly reduced rotational speeds within each speed range respectively between outer and inner circumference, with the prescription that a switching to a lower speed automatically ensues using control means when vibrations occur. A manually actuatable key for switching the drive into a speed range respectively lower by one step (n-1) is allocated to the control means for speed reduction.
Advantageous developments of the present invention are as follows.
The key for switching into a lower speed range is combined with the control key for the CD drawer transport and respectively one of the two functions can be triggered dependent on the duration of the key pressure.
The control key for the drawer transport is controllable such that, given brief-duration activation of the key, a speed reduction is triggered and, given longer key pressure, a transport motion of the CD drawer is triggered.
Advantageous developments of the invention are recited below. It is especially advantageous when the control key for switching the drive into a lower speed range is combined with the control key for the CD drawer transport because there is usually hardly any space for a further operating key given traditional drives. Dependent on the duration of the key pressure, either the function of speed reduction or the function of drawer transport is triggered.